Rationally I don't see Wizards restricting themselves, but in terms of JKR's determination to keep them so isolated, it would make sense within the context of the novels. I mean, who in their right mind would use a quill when you can use a pen? It's a mindframe that I don't think fits a rational economic system. A rational economic system would have a shadow world where Muggles and Wizards interact. But that doesn't happen in the series. Look at the big deal that is made of the Prime Minister being the ONLY one in the British cabinet who learns of his counterpart in the wizarding world. Personally, I don't think you can discount JKR's insistence on these world's being separate (and not equal).

I could see the Malfoys being colonialists. Having tea plantations with house-elves as pseudo slaves.